around the -40 mark. give or take. even unplugged its started but definately didnt like it. plugged in, no prob.
to the comment above somewhere, all vehicles in alberta for sure, maybe even all of canada now come from factory with block heaters.
and the other comment about parking lot plugs, yes they get damaged, but most times they are mounted on steel beams, posts, or some other elevated means that not gonna easily get wrecked.